tbuckley/cabot-search huggingface dataset:
Abstract P1031: A Novel Transcription Factor Combination For Direct Reprogramming To A Spontaneously Contracting Human Cardiomyocyte-Like State
Authors: Marisol Romero Tejeda, Hananeh Fonoudi, Carly J Weddle, Jean-Marc DeKeyser, Conrad L Epting, Paul W Burridge
Journal: Circulation Research (2022)

The reprogramming of somatic cells to a spontaneously contracting cardiomyocyte-like state using defined transcription factors has proven successful in mouse fibroblasts, but has been less successful with human cells, limiting the potential clinical applicability of this technology in regenerative medicine. We hypothesized that this issue is due to a lack of cross-species concordance between the required transcription factor combinations. Despite a decade of research, direct myocardial reprogramming still relies on overexpression of reprogramming factors first identified in mice: GATA4, MEF2C, TBX5. Using the Mogrify algorithm, we identified new candidate transcription factor combinations to induce cell conversion between human fibroblasts and cardiomyocytes. We developed an automated, high-throughput method for screening transcription factors, small molecules, and growth factors utilizing acoustic liquid handling and high-content kinetic imaging cytometry. Using this high-throughput platform we identified the combination of MYOCD, SMAD6, and TBX20 (MST) that can produce 40% TNNT2+MYH6+ cells in just 6 days and consistently produce spontaneous cardiomyocyte-like calcium transients and spontaneous contraction at just 25 days. These findings indicate that human cardiac direct reprogramming is feasible at similar levels to that achieved in the mouse and represents a step forward towards the possible clinical application of this direct cardiacreprogramming approach.
Abstract P1004: Macrophage Apoptotic Cell Receptor Mertk Triggers The Synthesis Of Arachidonic Acid Derivatives To Promote Cardiac Regeneration
Authors: Connor Lantz, Amanda Becker, Edward B Thorp
Journal: Circulation Research (2022)

Introduction: Macrophages (MΦs) are indispensable for regeneration of the mammalian neonatal heart. However, the underlying mechanisms by which neonatal MΦs sense the injured cardiac milieu and promote regeneration remain obscure. Utilizing single-cell transcriptomics, we previously observed a regenerative neonatal cardiac MΦ population that distinctly upregulates MerTK, an apoptotic cell receptor, compared to adult cardiac MΦs. Objective: We hypothesized that MerTK is required to program neonatal cardiac MΦs to secrete specialized pro-“regenerative” lipids to induce cardiomyocyte proliferation leading to heart regeneration. Methods: Postnatal day 1 and adult mice were subjected to cardiac injury via ligation of the left anterior descending artery. Single-cell transcriptomics, lipid-omics, and molecular approaches were utilized to determine the mechanisms by which neonatal MΦs regulate cardiac regeneration. Results: To determine the necessity of MΦ MerTK for cardiac regeneration, we employed a myeloid-specific knockout of MerTK ( mMertk -/- ) which failed to regain homeostatic cardiac function. We next performed single-cell transcriptomics on Mertk +/+ and Mertk -/- neonates to determine how MerTK activation reprograms neonatal MΦs for regeneration. Mertk +/+ MΦs significantly upregulated genes associated with arachidonic acid metabolism. Hypothesizing that arachidonic acid derivatives may be key signaling molecules for regeneration, we performed a targeted lipid-omics screen which revealed an increase in Thromboxane B 2 (TXB 2 ) in regenerating hearts but not within non-regenerative Mertk -/- hearts. Furthermore, addition of a TXA 2 agonist to neonatal cardiomyocytes in vitro significantly increases their proliferation by regulating the YAP/TAZ signaling. Alternatively, inhibition of thromboxane synthase in neonatal MΦs or thromboxane receptor on cardiomyocytes by small molecule inhibitors significantly abrogated the increase in cardiomyocyte proliferation by efferocytic Mertk +/+ neonatal MΦs. Conclusions: Altogether, our data suggest that MerTK programs neonatal cardiac MΦs to secrete TXA 2 to induce cardiomyocyte proliferation via the HIPPO-YAP/TAZ pathway prompting neonatal cardiac regeneration.
Abstract P1060: Sarcomeric Protein Phosphorylation Protects Mouse Hearts From Ischemia/reperfusion Injury
Authors: Buheng Wang, Seungho Jun, Gizem Keceli, Sara Rostampour, Nazareno Paolocci, Yuejin Li
Journal: Circulation Research (2022)

Introduction: Post-translational modifications of cardiac troponin I (cTnI), an essential sarcomeric protein, have been known to play a vital role in regulating heart function. Site-specific phosphorylation on cTnI Ser199 is upregulated in human ischemic heart failure, negatively affects diastolic function but preserves ejection fraction in mice in vivo , and promotes contractility recovery after ischemia/reperfusion (I/R) in male isolated mouse hearts. However, its cardioprotective mechanism is largely unknown. Hypothesis: We assessed the hypothesis that cTnI Ser199 hyperphosphorylation protects hearts during I/R via down-regulating reactive oxygen species (ROS). Methods: Due to the current methodology limitation, there is no way to phosphorylate one specific site on cTnI in vivo . We, therefore, generated a transgenic mouse model named TgD that carried Serine (S) to Aspartic Acid (D) mutation at cTnI Ser200 (equivalent to Ser199 in human sequence) to mimic the site-specific hyperphosphorylation, which was a widely accepted method for in vivo studies on sarcomeric protein phosphorylation. The cardiac function was examined using Langendorff isolated hearts with pacing at baseline and after 30-minute global ischemia followed by 2-hour reperfusion. Results: At baseline, TgD hearts (both genders, 7-8 mice/gender, age 3-5 months) showed comparable rate pressure product (RPP), left ventricular developed pressure (LVDevP), and d P /d t max but decreased d P /d t min relative to wildtype (WT) littermates. After I/R, TgD presented significantly better RPP, LVDevP, d P /d t max , and d P /d t min with remarkable contractile function recovery rate compared to WT (i.e., 47% ±2% vs. 24%±2% in RPP, P&lt;0.05) in both genders. The level of total ROS was similar in TgD and WT hearts at baseline. Although the ROS increased after I/R, it remained at a significantly lower level in post-I/R TgD hearts than WT controls, associated with differentially altered activities of antioxidant enzymes. Conclusions: In conclusion, human heart-failure-related cTnI Ser199 hyperphosphorylation protects heart function during global I/R in isolated mouse hearts in both genders . The protective mechanism, at least in part, involves the downregulation of ROS.
Abstract P3025: Prevalence Of Distinct Regional Wall Motion Abnormalities Among STEMI Patients Of North Indian Origin
Authors: Shiraz Rizvi S. Mohd, Sini Sunny, Irshad Wani, Farzana Mahdi, Namakkal-Soorappan Rajasekaran
Journal: Circulation Research (2022)

Background: Causal mechanisms and specific consequences of heart failure (HF) with preserved ejection fraction (HFpEF) are unknown. We compared the EF of ST-elevation myocardial infarction (STEMI) patients with the regional wall motion abnormalities (RWMA). Methods: 2D ECHO data in STEMI patients (n=217) was analyzed for HF with reduced systolic dysfunction (HFrEF), HFpEF, and RWMA. Inclusion: Patients with ≥50% stenosis and hypertension. Exclusion: S epticemia and malignancy patients. Results: Among 217 STEMI subjects, n=102 had either preserved or significantly increased ejection fraction (45-65%), indicating that &gt;47% of them were devoid of systolic dysfunction. The other two major groups were the subjects with moderately abnormal systolic dysfunction (HF r EF; EF &gt;31-42%) and severely abnormal dysfunction (HF r EF; EF &lt;30%). Over 50% of the subjects with HF p EF had basal-septum and inferior wall motion abnormalities, while the rest had apical septum, LAD territory and posterior wall impairments. Four patients displayed signs of mid-septal and anterior wall issues. While most of the HFrEF patients displayed wall motion defects in multiple regions, &lt;10 patients showed anterior wall motion abnormality. Severe HFrEF subjects (n=12) displayed global (all regions) motion defects, which contributes to end-stage heart disease. The RWMA seem to be unique for HFrEF and HFpEF among the STEMI patients. Conclusion: Results indicate that STEMI patients could be sub-grouped into both HF r EF and HF p EF. Further investigation into region-specific rate of remodeling, effect of lifestyle, food habits and pharmacological interventions will aid in improving clinical outcomes.
Abstract P2063: Circular RNA, circREGEN, Alters Cardiac Regeneration Through Cardiomyocyte Proliferation and Regulation of Oxidative Stress
Authors: Sarah Cushman, Arne Schmidt, Dongchao Lu, Ke Xiao, Cheng-Kai Huang, Naisam Abbas, Thomas Thum, Christian Baer
Journal: Circulation Research (2022)

Introduction: A subtype of non-coding RNA, circular RNAs (circRNAs), formed through backsplicing, are emerging as important regulators of cardiac development and cardiovascular diseases. CircRNAs are known to regulate gene expression through a multitude of functions. Prevalent circRNAs involved in cardiac development and potential regeneration can be determined by focusing on their differential expression in regeneration competent versus non-competent neonatal mouse hearts. We hypothesized that a circRNA that was both highly expressed in day 0.5 tissue and was upregulated under hypoxic conditions (simulating the uterine environment) would have a high potential for regeneration. Methods and Results: RNA-seq was performed in day 1 and day 7 mouse hearts and circREGEN was found to be downregulated on day 7 both in RNA-seq analysis and in neonatal mouse tissue samples using RT-PCR. Further circRNA validation was also performed and tissue distribution was measured, showing high expression levels in the heart, specifically, neonatal cardiomyocytes. HL-1 cells, neonatal mouse and rat CMs, neonatal living myocardial tissue, and human induced pluripotent stem cell (iPSC)-derived CMs were subjected to hypoxia (simulating this low oxygen uterine environment) and observed an increase in expression. This data showed that in addition to having high sequence conservation, circREGEN was functionally conserved across species as well. We decided to further examine the expression of circREGEN in living myocardial tissue, an ex-vivo model, after cryoinjury and saw an up-regulation. Further experiments were performed to functionally validate circREGEN using siRNAs and overexpression plasmids in neonatal mouse and rat CMs that showed a decrease in proliferation after circREGEN knockdown, and a reduction in ROS after overexpression, showing potential protective and regenerative effects of circREGEN. Conclusion: In conclusion, we have promising in vitro data, which warrants further functional investigation both in vitro, ex-vivo, and in vivo , with the ultimate goal to determine if circREGEN has therapeutic potential to regenerate damaged heart tissue after a myocardial infarct by stimulating the proliferation of CMs in the adult heart.
Abstract P2003: ER-resident UFBP1 Maintains ER Homeostasis And Represses Cardiac Inflammation To Constrain Pathological Cardiac Remodeling
Authors: Jie Li, Wenxia Ma, Aizhen Zhang, Juan Ayala, Honglin Li, Huabo Su
Journal: Circulation Research (2022)

Ufmylation is a novel protein modification by which protein substrates are covalently modified by the ubiquitin-like protein, UFM1 (ubiquitin-fold modifier 1) via a UFM1-specific E1-E2-E3 enzymatic cascade. Through its ability to regulate protein function, ufmylation participates in diverse pathophysiological events and is implicated in various human diseases. We recently reported that ufmylation is dysregulated by cardiomyopathy in both human and mouse hearts. Inhibition of ufmylation by targeting the E3 ligase, UFL1, in the heart evokes ER stress, leading to dilated cardiomyopathy and heart failure under resting and stress conditions, demonstrating its critical role in maintaining ER and cardiac homeostasis. However, how ufmylation regulates ER and cardiac function remain unclear. Here, we report that UFBP1 (UFM1 binding protein 1), an ER-resident ufmylation target, is a crucial downstream effector of ufmylation in the heart. UFBP1 is downregulated in UFL1-deficient hearts but upregulated in pressure overload hearts. Condition knockout (KO) of UFBP1 in mouse heart caused dilated cardiomyopathy during aging and exacerbated pressure overload-induced pathological cardiac remodeling. Of note, the timeline of disease progression in UFBP1 KO mice closely aligned with that of UFL1 KO mice. Transcriptomics analysis revealed the involvement of ER stress signaling and unexpectedly, inflammation in the pathogenesis. Biochemical analyses confirmed the pronounced ER stress, increased cytokine expression, and remarkable infiltration of inflammatory cells into the myocardium, which preceded the severe cardiac phenotype. Alleviation of ER stress via TUDCA administration mitigated UFBP1KO-induced cardiac dysfunction, suggesting a causal role of ER stress in the pathogenesis. Re-expression of wild-type UFBP1, but not its ER-binding–deficient mutant, in UFBP1 KO hearts rescued the pathological cardiac phenotype. UFPB1 expression was stabilized by UFL1, and depletion of UFBP1 in cardiomyocytes (CMs) induced ER stress and promoted cell death, recapitulating most aspects of UFL1-deficient CMs. Collectively, our data suggest that ER-resident UFBP1 represses ER stress and cardiac inflammation to constrain pathological cardiac remodeling.
Abstract P1089: Short-QT &amp; Long-QT Associated Trpm4 Mutations
Authors: Gary L Aistrup, Ryan Pfeiffer, Robert Goodrow, Jon Cordeiro, Adife G Ercan-Sencicek, Mayuri Desai, Maria Kontaridis
Journal: Circulation Research (2022)

Cardiac arrhythmias are responsible for 200-300 thousand deaths/year. Despite considerable research effort, much remains to be elucidated concerning the underlying mechanisms of arrhythmogenesis. Mutations in transient receptor potential melastatin 4 (TRPM4), a widely expressed Ca 2+ -activated nonselective cation channel, have been associated with causing cardiac arrhythmias. However, direct genotype-phenotype correlation of arrhythmogenic TRPM4 mutant variants are often complicated, as this channel is not primary to the cardiac action potential. Here, we assessed the electrophysiological and post-transcriptional molecular properties of a single mutation (R892C)-TRPM4 associated with short QT syndrome (SQTS) and a triple mutation (R250C|A432T|G582S)-TRPM4 associated with long QT syndrome (LQTS), using stably transfected HEK293 cells. Overall, protein expression of the triple mutant was found to be significantly reduced, with increased proteasomal degradation, but enhanced SUMOylation, as compared to either WT or the single R892 mutant TRPM4 channel. Consequently, expression of R250C|A432T|G582S-TRPM4 was significantly lower at the cellular membrane than either R892C- and WT-TRPM4. In contrast, while total expression of TRPM4 was not significantly different between WT and the R892C single mutant, although the R892C exhibited increase aggregation. Patch-clamp cellular electrophysiology experiments indicated that both single and triple TRPM4 mutant channels could be activated by lower Ca 2+ concentrations compared to WT. However, R892C-TRPM4 channels inactivated faster, while R250C|A432T|G582S-TRPM4 channels inactivated much slower compared to WT. These data as obtained in our homologous recombinant overexpression system reveal that while the R892C-TRPM4 mutant variant exhibited normal-to-higher levels of expression and increased Ca 2+ -activation sensitivity, its tendency to aggregate combined with faster inactivation can result in overall loss-of-function compared to WT, correlative with SQTS. Conversely, while the R250C|A432T|G582S-TRPM4 mutant variant exhibited reduced expression and perturbed trafficking, its increased Ca 2+ -activation sensitivity and slow inactivation can result in overall gain-of-function compared to WT, correlative with LQTS.
Abstract P3075: Hippo Pathway In Cardiac Fibroblast Regulates Macrophage Recruitment Following Injury
Authors: Fansen Meng, Xiao Li, Rich Gang Li, Chang-Ru Tsai, James F Martin
Journal: Circulation Research (2022)

Background: The evolutionary conserved Hippo signaling pathway (HSP) is an inhibitor of tissue regeneration, including the Lats1/2 kinases that phosphorylate and inactivate YAP and TAZ. Emerging data indicate that HSP regulates innate immunity, inflammation, and autoimmune diseases. However, the role of HSP in post-MI inflammation is poorly understood. Methods: Single-cell RNA-sequencing (scRNA-Seq) and spatial transcriptomics were utilized in cardiac fibroblast (CF)-specific-Lats1/2 knockout (Lats CKO) mouse heart. Flow cytometry, immunofluorescence (IF), and echocardiogram (Echo) were used to describe the phenotype in ventricle of Lats CKO mouse heart with/out Ccr2 knockout. Results: We integrated our scRNA-Seq data in Lats CKO mouse heart with three published data sets of MI mouse heart. A CF subcluster with elevated YAP activity and expressing chemokines Ccl2 and Ccl7 (Ccl2/Ccl7+ CFs) and macrophages (Macs) expressing Ccr2, the receptor for Ccl2/Ccl7 (Ccr2+ Macs), were identified, which suggests a signaling transduction from Ccl2/Ccl7+ CFs to Ccr2+ Macs in post-MI hearts. To figure out the function and mechanism of this specific cell communication, we employed a Lats CKO mice model which mimics the post-MI heart and exhibits high YAP activity and conformed the cell communication between Ccl2/Ccl7+ CFs and Ccr2+ Macs by spatial transcriptomics. Furthermore, Ccr2 loss of function in Lats CKO mice suppressed Mac expansion and CF proliferation. Consistently, Ccr2 knockout reversed the phenotype presenting smaller left ventricle chamber in Lats CKO mouse heart because of CF proliferation. Conclusion: YAP target genes Ccl2 and Ccl7 in CFs are responsible for Ccr2+ Macs recruitment and the recruited Ccr2+ Macs in turn promote CF proliferation post-MI.
The effects of five years of nocturnal cuirass-assisted ventilation in chest wall disease
Authors: M Jackson, W Kinnear, M King, S Hockley, J Shneerson
Journal: European Respiratory Journal (1993)

We investigated the long-term effectiveness of cuirass-assisted ventilation, and examined whether mortality and morbidity could have been predicted at the time of admittance. Twenty five patients were commenced on nocturnal cuirass-assisted ventilation between 1983 and 1985, 10 with scoliosis or kyphosis, 8 with a thoracoplasty and 7 with neuromuscular disease. Mean pretreatment vital capacity was 30% of predicted, and arterial carbon dioxide tension (Paco2) was 8.2 kPa (62 mmHg). Fifteen patients were alive 5 yrs later. Two had discontinued assisted ventilation, both dying soon afterwards, and three had been changed to intermittent positive pressure ventilation. Survival could not have been predicted from age, severity of disease, lung volumes or arterial blood gases at presentation. Paco2 in the survivors had risen from a mean of 6.1 kPa (46 mmHg) after one year to 6.8 kPa (52 mmHg) after 5 yrs (p &lt; 0.05), but remained significantly less than at presentation. There were no significant change in arterial oxygen tension (Pao2), lung volumes, respiratory muscle strength, haemoglobin, right heart failure, exercise tolerance, mental function and symptom scores after 5 yrs, compared to after 1 yr. The median amount of time spent in hospital declined from 15 days per patient in the first year after initial discharge with cuirass-assisted ventilation, to between 3-5.5 days per patient in subsequent years. We conclude that nocturnal cuirass-assisted ventilation has a role in long-term management of patients with neuromuscular and skeletal chest wall disorders. A randomized comparison with nasal intermittent positive pressure ventilation is now indicated.
Abstract P3085: The Human Myocardium Harbors A Population Of B Cells With A Distinctive Gene Expression Signature Conserved Across Species
Authors: Kevin Bermea, Nicolas Kostelecky, Sylvie Rousseau, Chieh-Yu Lin, Luigi Adamo
Journal: Circulation Research (2022)

Introduction: Investigations in murine models have identified myocardial B cells with a characteristic gene expression signature and have pointed at B cells as a promising target to develop novel therapies for heart failure. However, there is almost no data on B cells in the human heart. Methods and Results: We performed immunostaining to characterize the amount and distribution of B cells in human hearts. In 12 healthy hearts collected at autopsy, we found 1.4 ± 1.6 CD20+ B cells per high power field. The number of CD3+ T cells was almost 20 times higher (26.8 ± 28.6, P&lt;0.001). Utilizing CD31 (endothelial marker), we found that human myocardial B cells were both in intravascular and interstitial locations, with a slight prevalence for the interstitium (P=0.006). Parallel analysis of tissue collected post-mortem or at the time of VAD placement showed that analysis of post-mortem tissue did not introduce bias. To gain insight into the biology of human myocardial B cells we first analyzed publicly available single cell sequencing datasets of myocardial (Heart Cell Atlas) and peripheral blood cells (10X Genomics). We found that the human myocardium harbored a minor population of B1 cells and a larger population of B2 cells, and that myocardial B cells had a gene expression signature distinct from that of peripheral blood B cells. We validated these findings on primary B cells sorted from the heart and peripheral blood of 2 patients subjected to LVAD implant (binomial for concordance p=4.13e-32). To identify biological pathways upregulated in myocardial B cells across species, we compared differential gene expression in myocardial vs peripheral blood B cells across the studied human datasets and published rodent datasets. We identified 703 genes with consistent differential gene expression (binomial p=2.9e-48). KEGG pathway analysis of these genes highlighted “B cell receptor signaling pathway”, “Antigen processing and presentation” and “Cytokine-cytokine receptor interaction” among the top conserved pathways upregulated in cardiac B cells (FDR &lt;0.001). Conclusions: The human heart harbors a small population of B cells that is comprised of both B1 and B2 cells. Human myocardial B cells have a distinct gene expression signature that is conserved across species.